Tension device for sewing-machines.



No. 686,0| 3., Patented Nov. 5, l90l.

H. A. WEBSTER.

TENSION DEVICE FOR SEWING MACHINES.

(Application filed May 2, 1900.)

(No Model.) 3 Sheets-Sheet I.

No. 685,0I3. V Pafented Nov. 5, I90].

u. A. WEBSTER.

TENSION DEVICE FOR SEWING IIIAGHINES.

(Application filed May 2, 1900.) (No Model.) 3 Sheets-Sheet 2.

H. A. WEBSTER.

TENSION DEVICE FOR SEWING MACHINES.

(Application filed May 2, 1900.)

No. 686,0!3. Patented Nov. 5, [90L (No Model.) 3 Sheets-Shut 3.

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UNITED STATES PATENT OFFICE.

HAROLD A. WEBSTER, OF HAVERHILL, MASSACHUSETTS, ASSIGNOR TO GOODYEARSHOE MACHINERY COMPANY, OF PORTLAND, MAINE, A

CORPORATION OF MAINE,

YTENSION oEvlcE FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent N o. 686,013, datedNovember 5, 1901.

Application filed May 2, 1900.

To all whom it may concern.-

Be it known that I, HAROLD A. WEBSTER, a

citizen of the United States, residing at Haverdo hereby declare thefollowing to be a full,

clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

The present invention relates to an improvement in tension devices forsewing-machines, and more particularly to an improvement in tensiondevices of thecharacter described in my copending applications, SerialNo. 686,422, filed July 20, 1898; Serial No. 696,812, filed November 18,1898, and Serial No. 727,265, filed August 15, 1899, which areespecially adapted for use in connection with wax-threadsewing-machines.

The object of the present invention is to make an improved tensiondevice operating on the same general principles as those of theabove-named applications.

To the above end the present invention consists of the improved tensiondevice hereinafter described and claimed.

In the drawings illustrating the preferred embodiment of my invention,Figure 1 is a side elevation of the device attached to the rear of thewell-known Goodyear welt and turn machine, of which the upper part ofthe stand and the lower part of the head are shown. Fig. 2 is a plan.Fig. 3 is a section on the line w a: of Fig. 1. Fig. 4 is an elevationlooking in the direction of the arrow y of Fig. 2, the base of the framebeing broken away. Fig. 5 is a section on line a z of Fig. 4. Fig. 6 isan elevation of the outside, and Fig. 7 is an elevation of the inside,of the tension-adjusting wheel. Fig. 8 is a face view of one of theclutch operating disks hereinafter described; and Fig; 9 is a section oftheclutch operating disks, showing the oppositely-inclined bottoms ofthe ball-receiving recesses.

In the illustrated embodiment of the invention the frame 1 of thetension device is secured to the rear of the base 2 of the head of thesewing-machine in any desired manner,

Serial No. 15,224. (No model.)

as by the bolts 3. The frame is projected rearwardly and supports theoperative parts of the tension device. The tension-wheel or thread-truck4 is revolubly supported upon the stud 5, which is mounted in therearend of the frame 1 and secured in position by the nut 6 andclamping-screw 7, which clamps the slotted bearing for the stud 5together securely to hold the said stud 5 from rotation. Thetension-wheel 4 is provided with a friction-face 8, which is adapted tobe engaged by an opposing friction-face 8 of a sleeve 9, loosely mountedon said stud, the construction of the friction-faces being such thatwhen the sleeve 9 is forced toward the tension-wheel 4 it will engageand hold the same from rotation. Thus the two friction-faces comprise afriction clutch which may be opened and closed to release or hold theten-' sion-wheel.

The means provided for moving the sleeve 9 toward the tension-wheel 4consists of two disks 10 and 11, the former of which is rigidly securedto the stud 5, and the other of which is rigidly secured to the sleeve9. These disks are provided on their adjacent faces with recesses 12,the bottoms of which are inclined in opposite directions and in whichballs are placed. The above arrangement is such that when a rotationalmovement is imparted to the sleeve 9 the balls 13 will roll up theoppositely-inclined bottom surfaces of the recesses 12 and force thesleeve 9 toward the tension-wheel 4, thereby clamping the tensionwheeland holding it from rotation.

I have found when a screw-thread is used to force the clutch-facestogether and a heavy tension is employed that sometimes the screwthreadwill bind or stick and that by substituting the ball-disks for thescrew-thread this binding or sticking is obviated, thus contributingmaterially to certainty of'operation of the clutch at the predeterminedtension. The present construction therefore removes an ingredient ofpossible uncertainty in the operation of the prior construction.

The disk 10 is held in place by a nut 36, screwed onto the reduced endof the stud 5,

firmly against the shoulder 37, so that the said disk is held from anymovement on the stud away from the tension-wheel 4. The disk is heldfrom rotation by a pin 14, which passes through a hole in the nut 36 andenters a corresponding hole in the disk 10, so that the said disk isthus held from rotational movement and from movement away from thetensionwheel 4. The other disk 11 is rotatably mounted upon the stud 5and is secured to the sleeve 9 by means of the pin 15, which passesthrough a hole in the arm 16 of the sleeve 9 and enters a correspondinghole in the disk 11. This arrangement is such that the disk 11, while itis free within certain limits to move longitudinally upon the stud 5, isheld from rotational movement thereon except in conjunction with arotational movement with the sleeve 9. The sleeve 9 is provided with anarm 17, which carries a stud 18, upon which is loosely moun ted a smallthread-truck 19, about which the thread passes after leaving thetension-wheel on its way to the stitch-forming mechanism.

The lead of the thread is illustrated in Fig. 1. It goes up from thewax-pot around the tension-wheel 4, thence around the threadtruck, whichis mounted on the arm 17 of the sleeve 9, thence passes up ward andforwardly to the stitch-forming mechanism, the above arrangement beingsuch that a pull upon the thread by the stitch-forming instrumentaltties tends to rotate the sleeve 9, and when rotated in this directionthe balls 13 roll into the deeper portion of the recesses 12 and thetension-Wheel is released.

Means are provided normally tending to retate the sleeve 9 upon the stud5 in thedirection to cause the balls 13 to roll to the higher parts ofthe recesses 12, so as to force the sleeve 9 against the tension-Wheel 4to clamp and hold the same. In the present form of my invention thesemeans are so constructed that the pressure of the friction-faces uponeach other can be adjusted with the utmost nicety, so'that the amount oftension which is required to be applied to the thread in order torelease the tension-wheel is susceptible of the most accurateadjustment. The arm 16, before referred to as projecting forwardly fromthe sleeve 9, is provided with a lug 20, to which a spring is attached,and suitable devices are provided for regulating the tension of thespring, so as to determine the pressure with which the friction-faceswill be forced against each other, and thus the 7 amount of tensionrequired upon the thread in order to release the tension-wheel 4. Myinvention is not limited to any particular means for accomplishing thispurpose, but I have shown in the drawings the device which I prefer.They consist of a hand-wheel 21, whichis loosely mounted upon the end ofthe stud 5 and held in place by a washer 22 and screw 23. One end of thespring is attached to the lug 20 on the arm 16 and the other end of thespring is attached to a lug 24 on the se m hand-wheel 21, the springbeing wrapped loosely around the disk 11, which is provided with agroove 25 to hold the spring from accidental displacement therefrom. Arotation of the hand-wheel in the direction of the arrow 26 Willincrease the tension on the spring and a rotation in the oppositedirection will decrease it. Means are provided to hold the hand-wheel inany desired position, and such means are shown in the drawings as thepawl 27, which is pivoted at 28 to the hand-wheel and the engaging toothof which is normally pressed inward by the spring'29, which consists ofa piece of spring-wire wound around a pin 30, bearing outward againstthe inside of the rim 31 of the hand-wheel 21 and inwardly against thepawl 27. The pawl is provided with the outwardly-projected end,whichextends slightly beyond the surface of the periphery of the hand-wheel,so as to be in convenient position to be engaged by the hand whilegrasping the wheel to adjust the tension of the spring. The toothed endof the pawl engages the ratchet-teeth 32,'formed on the periphery of thenut 36. The above arrangement is such thatby turning the hand-wheel tothe right, as seen in Fig. 6, the tension on engrave graduating-marks,the mark opposite the index 33 on the washer 22 indicating, if desired,the tension in pounds necessary to be applied to the thread in order torelease the tension-wheel, or, in other words, the tension under whichthe machine is working. In the machine of the drawings two ratchetteethcorrespond to one mark on the graduatingscale, so that if the scaleindicates pounds the tension can be adjusted to halfpounds.

Means are provided for releasing the tension-wheel when the sewing of ashoe is completed. To this end a bell-crank lever 34 is pivoted to theframe 1, with one end pro j ected over the forwardly-projected arm 16 ofthe sleeve 9, so that when the lever 34 is oscillated to depress the arm16 the sleeve 9 will be oscillated thereby against the force of thespring to release the tension-wheel 4. The down-hanging end of thebell-crank lever 34 is connected with any suitable devices for operatingit, as the rod 35, chain 39, and rock-shaft 40 of the well-knownGoodyear welt and turn machine.

Having thus described my invention, I claim as new and desire to' secureby Letters Patent of the United States 1. A tension device forsewing-machines, having, in combination,a thread-truck,a looking devicetherefor, a support for said looking device, said support and lockingdevice carrying complementary inclines, and a ball interposed betweenthe complementary inclines, substantially as described.

2. A tension device for sewing-machines,

IIO

having, in combination,a thread-truck,a looking device therefor, and asupport for said locking device, about which it is arranged to turn,said support and locking device having a series of complementaryinclined contactfaces separated by a series of balls for moving thelocking device toward the threadtruck as said locking device is turnedon its support, substantially as described.

3. A tension device for sewing-machines, having, in combination,athread-truck,a looking device therefor, a support for said lookingdevice, two ball-disks mounted on said support, the one secured to thesupport and the other secured to the locking device, and ballsinterposed between the said ball-disks, substantially as described.

4. A tension device for sewing-machines, having, in combination,athread-truck,a looking device therefor, a support for said lookingdevice about which it is arranged to turn,

a ball-disk secured to said support provided with ball-recesses in itsface, having inclined bottoms, a complementary ball-disk having similarball recesses in its face rotatably mounted upon said support and meanssecured to the said latter ball-disk controlled by a pull of the threadfor rotating the latter ball-disk to actuate the locking device,substantially as described.

5. A tension device for sewing-machines, having, incombination,a'thread-truck,a locking device therefor, movable axiallytoward a support for said locking device, a stationary ball-diskprovided with recesses secured to said support, a movable ball-disksecured to 7 said locking device provided with ball-recesses in itsface, the said recesses being inclined in opposite directions, ballsmounted in said recesses, an idle thread-truck mounted on said idlethread-truck arm of the locking device, a ratchet-and-pawl adjustingdevice, and a spring connected at one end to the said arm for the springof said locking device and at the other end to said ratchet-and-pawladjusting device, whereby the tension of the spring may be adjusted,substantially as described. I

6. A tension device for sewing-machines, having, in combination,athread-truck,a locking device therefor, a support for said lookingdevice, said support and locking device carrying complementaryinclines,a ball interposed between the inclines, and meansactingnormally to cause the locking device to lock the thread-truck,substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

HAROLD A. WEBSTER.

Witnesses:

HORACE VAN. EVEREN, ALFRED H. HILDRETH.

